At present, video monitors have been widely used in urban daily management.
Commonly used camera layout methods include: abstracting an objective world as points (such as intersections, ATMs, etc.), lines (roads), and surfaces (CBDs, large shopping malls, etc.), then calculating a coverage region of monitor points, judging a rationality of the monitor point layout according to whether the coverage region includes the objective world or a degree to which the objective world is included, and adjusting and obtaining a final camera layout requirement diagram according to the judging result to perform a camera layout.
This layout method may take a coverage degree of cameras in a monitored region as a key evaluating parameter. For example, by calculating the coverage degree of the cameras, a detailed situation of camera coverage of the monitored region, etc., one or more indicators of evaluating the layout is established. This process is often complicated. For example, camera coverage involves type, focal length, rotation angle, lens, resolution and installation height of cameras, and monitor targets involve different entities in the objective world. If taking the entities in the objective world into consideration, requirements for data will be increased several-fold, because although a case for one entity may serve as a reference for that of another entity, differences somehow persist between cases for different entities.
Another drawback of this method is that importance of different entities of the objective world is not determined and distinguished, that is, important regions and non-important regions apply a same layout method, which is likely to result in inadequate monitor points in important regions and redundant monitor points in non-important regions.
When evaluating the rationality of a video monitor layout, a key indicator is whether key regions are covered, that is, as many monitor points as possible are arranged in the key regions to ensure that the key regions are fully covered and efficiently monitored. In an overall layout of the monitor points, clear requirements will be generally given based on an object to be monitored, such as covering major banks, supermarkets and other crowded regions. However, abstracting objective things into a data structure of points, lines and surfaces and performing operations based on vector data may ignore nature of the objective things.
For example, in a monitor point layout, it is possible that insufficient cameras are arranged in the key regions where a video acquiring frequency is high while cameras are arranged in some non-key regions with a same density due to ignorance of an actual situation of the regions. This leads to a waste of resources to some extent, and monitor effect of the key regions may be poor as a result of the insufficient arrangement of cameras.
In the related art, for the analysis of a rationality of camera distribution, operating frequencies of cameras may be counted. For example, cameras which are used at a frequency higher than an average may be determined and thus considered that these cameras were reasonably utilized. Cameras with an operating frequency lower than the average may be considered to be unreasonably distributed. However, this analysis method may cause a mis-judgement. For example, for a key region, a plurality of cameras may be usually deployed simultaneously to achieve full coverage of the region. Monitoring of the region by a user is accomplished through a camera group, and the user may often view monitor videos of the camera group, but a frequency of operation for a single camera is not high. In this case, if the frequency of a single camera is counted according to the above method, an analysis result that the group of cameras has a low utilization rate will be obtained, and the analysis result does not comply with the actual situation.